The present invention generally relates to windows having variable transmittance light filters, and more specifically to windows including electrochromic light filters.
Variable transmittance light filters, such as electrochromic light filters, have been proposed for use in architectural windows, skylights, and in windows and sunroofs for automobiles. Such electrochromic light filters reduce the transmittance of direct or reflected sunlight during daytime through the window, while not reducing such transmittance during nighttime. Not only do such light filters reduce bothersome glare and ambient brightness, but they also reduce fading of interior materials and heat load caused by the transmittance of sunlight through the window.
Electrochromic windows have not been widely accepted commercially for several reasons. First, they tend to be very expensive due to the cost of materials required for their construction, and their complex construction makes mass production difficult. Additionally, electrochromic windows have tended to have a lower life expectancy than conventional windows due to degradation of the electrochromic materials used in the window. The combination of added cost and lower life expectancy has deterred many architects and builders from using electrochromic windows.